I am sure most of you guys know about this site. Its a very good website from Zap, who works at Mental Images, sharing updated tips and tricks shading and rendering, and the newest stuff related to Mental Ray.
I'm putting it here as a reminder to myself too. :)
I am now at this page, but haven't gotten around to reading it. It's talking about a set of production shaders that is littled known to most artists using Mental Ray.